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First Proof That Ghrelin Increases Appetite and Food Intake in Humans

RPEP-007052001Wren, A M; Seal, L J; Cohen, M A; Brynes, A E; Frost, G S; Murphy, K G; Dhillo, W S; Ghatei, M A; Bloom, S R
RCTStrong evidence
The takeaway

Intravenous ghrelin infusion potently increased appetite, food intake, and GH secretion in healthy humans — the first demonstration that ghrelin drives human hunger, not just rodent appetite.

First human proof

IV ghrelin increased both hunger ratings and actual food intake in healthy humans — confirming the hunger hormone works in people, not just rats

What the researchers found

IV ghrelin infusion in healthy humans increased subjective appetite ratings and food intake significantly, alongside GH stimulation, providing the first proof that ghrelin is a human hunger hormone.

Why it matters

Confirming ghrelin drives human appetite transformed it from an interesting lab finding to a validated drug target. It justified developing ghrelin-based drugs for cachexia, anorexia, and potentially obesity (via antagonists).

How the study worked

Randomized, placebo-controlled study in healthy volunteers. IV ghrelin infusion with subjective appetite visual analog scale ratings and ad libitum buffet food intake measurement. GH measured.

What this study cannot tell us

Healthy volunteers; responses in patients with appetite disorders may differ. IV administration may not predict responses to long-acting formulations. Acute study doesn't predict chronic appetite effects.

How to read the evidence

Strong evidence from a placebo-controlled study with both subjective (appetite ratings) and objective (food intake) endpoints in humans.

When this study was published

Published in 2001. This landmark study has been cited extensively and confirmed by numerous subsequent human ghrelin studies.

The bigger picture

This landmark study confirmed the animal findings in humans, validating ghrelin as the hunger hormone and launching a new era of appetite biology and drug development.

Questions still open

  • Can ghrelin treatment help cancer cachexia or anorexia nervosa?
  • Does chronic ghrelin elevation lead to sustained appetite increase?
  • Can ghrelin antagonists suppress human appetite for obesity treatment?

Common questions

Does ghrelin really make you hungry?
Yes — this study proved it in humans for the first time. When healthy people received ghrelin, they felt hungrier and ate significantly more food. It's truly the body's hunger hormone.
Could this help people who can't eat?
Potentially. People with cancer, HIV, or eating disorders who can't eat enough might benefit from ghrelin to stimulate their appetite. Ghrelin-based drugs for cachexia and appetite disorders are being developed.

Read the original research

Ghrelin enhances appetite and increases food intake in humans.

The Journal of clinical endocrinology and metabolism, 86(12), 5992

View on PubMed ↗

Citation

Wren, A M; Seal, L J; Cohen, M A; Brynes, A E; Frost, G S; Murphy, K G; Dhillo, W S; Ghatei, M A; Bloom, S R. (2001). Ghrelin enhances appetite and increases food intake in humans.. The Journal of clinical endocrinology and metabolism, 86(12), 5992.